CDD Implement TODO (explicit-only)

Implement exactly one TODO step in the target repo, run that step's Automated checks, update the active TODO file to mark that step's tasks done on success, and return a UAT checklist.

Do not invent missing product, architecture, sequencing, or validation decisions during implementation. If the selected step is not decision-complete, patch the TODO step first.

Flow

1. Read AGENTS.md, README.md, the active TODO*.md, and any files needed for the chosen step.
2. Resolve the requested step before asking anything:
   • If the user explicitly names a step (for example step 8, step 08, step 008, or an exact step heading), search TODO.md and TODO-*.md and normalize numeric step identifiers so 8, 08, and 008 are equivalent.
   • If exactly one step matches, treat that step as authoritative and continue immediately without asking for confirmation.
   • Ask only when the step is ambiguous (for example the same step number exists in multiple TODO files) or cannot be resolved from the user’s request.
   • If the user did not specify a step at all, ask for the exact step to implement.
3. If the step is underspecified, draft a minimal TODO patch and ask approval before implementing.
   • Treat the step as underspecified when it is missing Tasks, Automated checks, or UAT.
   • Also treat it as underspecified when the task list does not identify the concrete target boundary or subsystem, the contract/interface/behavior change to make, the sequencing needed across multiple surfaces, or the validation evidence required by the goal.
   • If the step implies migration, snapshot/audit retention, compatibility, or must-preserve behavior, treat those omissions as underspecification unless the step captures them in Constraints, Implementation notes, or equivalent local sections.
   • Preserve the repo's step template when possible, but add Constraints, Implementation notes, or equivalent detail when that is the smallest change that makes the step decision-complete.
4. Implement the step with minimal diffs.
5. Run the step’s listed Automated checks (or the repo’s stricter standard checks if they exist).
6. If implementation and checks pass, update only the selected step in the active TODO*.md file to show its Tasks are done:
   • If the step's Tasks section already uses markdown checkboxes, change unchecked task items from [ ] to [x].
   • If the step's Tasks section uses plain bullets, rewrite only those task bullets into checked markdown checkboxes while preserving the task text and order.
   • Do not add a new step-level Status: field or any other completion marker.
   • Do not mark the TODO step done if implementation or checks failed.
   • Do not modify future or unrelated steps.
7. Update the matching journal file only when changes are non-trivial, per AGENTS.md.
   • In single-journal mode, update docs/JOURNAL.md.
   • If the selected step is in TODO-<area>.md, treat matching docs/journal/JOURNAL-<area>.md as the default hot journal in split-journal mode.
   • In split-journal mode, use docs/journal/JOURNAL.md only for repo-wide or cross-cutting notes.
   • Do not duplicate the same journal entry across multiple journal files.
8. Final report format: follow the target repo’s AGENTS.md “Output Format Per Turn”.
   • Explicitly state which TODO*.md file and step were updated to mark the completed tasks done.

Resolution examples

• $cdd-implement-todo step 008 + one matching Step 08 in the repo: implement immediately, no reconfirmation.
• $cdd-implement-todo step 008 + matches in TODO.md and TODO-foo.md: ask which TODO file or exact heading to use.
• $cdd-implement-todo with no step argument: ask which step to implement.
• A matched step missing Tasks, Automated checks, or UAT: ask approval only for the minimal TODO patch needed to make the step executable.
• A matched step with vague tasks such as "support DOCX export" or "simplify the report" but no concrete boundaries, sequencing, or proof: ask approval for the minimal TODO patch needed to make the step decision-complete before implementing.
• A matched step that passes implementation and checks: mark only that step's task items done in the active TODO file before the final report.